BBY2KS2K

The girl Iam dating has a 1988 Jeep Cherokee with a 4.0 liter I-6 and an automatic transmission. She insists on putting the lever in "D" when driving less than say 45 MPH and only shifts to "OD" when driving above 45 like at highway speeds. I guess one of her friends told her that the transmission would last longer that way. I tried explaining to her that this sounded like B.S. The only time she would need to put in "D" versus "OD" is to prevent the transmission from "hunting" or going back and forth between gears when going up a steep hill, towing something or to engine brake when going down a steep hill, not for normal driving. I don't think manually shifting will hurt anything, it just seems pointless. I don't know, maybe Iam wrong. My 94' Corsica has a 4 speed auto with overdrive. I just leave it in "OD". Does anybody else manually shift their automatic car?

moparacker

Most OD's with kick it at around 35-40mph by themselves when cruising at light throttle. The only thing it can really do to hurt is that it makes the motor rev more than required. This in turn also increases gas mileage.

Just tell her to keep it in 'OD' at all times.